Societe Generale and U.S. wealth management company Rockefeller Financial Services announced a global alliance on Tuesday in the private banking sector.
As part of the deal, SG Private Banking has bought a minority equity stake in Rockefeller Financial Services.
The companies said they would work together to "share areas of expertise and jointly serve the financial needs of ultra high net worth individuals and family offices around the world".
Rockefeller had $29 billion of assets under management as of March 31 and is headquartered in New York.
SG Private Banking has assets of around 71 billion euros ($109.1 billion) under management and has been one of the best-performing divisions of SocGen in recent months.
Last year, SocGen's SG Hambros division bought ABN Amro Private Banking London.
SocGen is trying to battle back from a 4.9 billion euro loss disclosed in January which the bank said was caused by rogue deals carried out by Jerome Kerviel, a 31-year-old junior trader at the bank.
Kerviel was freed from prison in March after an appeal against his detention but he remains under formal investigation for breach of trust, computer abuse and falsification.
SocGen shares closed at 58.14 euros on Monday.
The stock has fallen around 37 percent since the start of 2008, compared to a 26 percent fall in the DJ Stoxx European banking sector.